#4  判断用户输入的年份是否为闰年

if __name__ == '__main__':
 year = input ('请输入一个年份:')
 year = int(year)
 if year % 400 == 0:
     print("年份%d是闰年" %year)
 elif year % 4 == 0 and year % 100 != 0:
     print("年份%d是闰年" % year)
 else:
     print("年份%d不是闰年" % year)